Collapse AudioRendererMixer and OnMoreDataResampler into AudioTransform.

media/base/fake_audio_render_callback.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_FAKE_AUDIO_RENDER_CALLBACK_H_
 #define MEDIA_BASE_FAKE_AUDIO_RENDER_CALLBACK_H_
 
+#include "media/base/audio_converter.h"
 #include "media/base/audio_renderer_sink.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 namespace media {
 
 // Fake RenderCallback which will fill each request with a sine wave.  Sine
 // state is kept across callbacks.  State can be reset to default via reset().
-class FakeAudioRenderCallback : public AudioRendererSink::RenderCallback {
+// Also provide an interface to AudioTransformInput.
+class FakeAudioRenderCallback
+    : public AudioRendererSink::RenderCallback,
+      public AudioConverter::InputCallback {
  public:
   // The function used to fulfill Render() is f(x) = sin(2 * PI * x * |step|),
   // where x = [|number_of_frames| * m, |number_of_frames| * (m + 1)] and m =
   // the number of Render() calls fulfilled thus far.
   explicit FakeAudioRenderCallback(double step);
   virtual ~FakeAudioRenderCallback();
 
   // Renders a sine wave into the provided audio data buffer.  If |half_fill_|
   // is set, will only fill half the buffer.
-  int Render(AudioBus* audio_bus, int audio_delay_milliseconds) OVERRIDE;
+  virtual int Render(AudioBus* audio_bus,
+                     int audio_delay_milliseconds) OVERRIDE;
   MOCK_METHOD0(OnRenderError, void());
 
+  // AudioTransform::ProvideAudioTransformInput implementation.
+  virtual double ProvideInput(AudioBus* audio_bus,
+                              base::TimeDelta buffer_delay) OVERRIDE;
+
   // Toggles only filling half the requested amount during Render().
   void set_half_fill(bool half_fill) { half_fill_ = half_fill; }
 
   // Reset the sine state to initial value.
   void reset() { x_ = 0; }
 
   // Returns the last |audio_delay_milliseconds| provided to Render() or -1 if
   // no Render() call occurred.
   int last_audio_delay_milliseconds() { return last_audio_delay_milliseconds_; }
 
+  // Set volume information used by ProvideAudioTransformInput().
+  void set_volume(double volume) { volume_ = volume; }
+
  private:
   bool half_fill_;
   double x_;
   double step_;
   int last_audio_delay_milliseconds_;
+  double volume_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeAudioRenderCallback);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_FAKE_AUDIO_RENDER_CALLBACK_H_